galumph v.informal move in a clumsy, ponderous, or noisy manner.
-DERIVATIVES galumphing adj.
-ORIGIN 1871 (in the sense 'prance in triumph'): coined by Lewis Carroll in Through the Looking Glass; perhaps a blend of GALLOP and TRIUMPH.

jabberwockyn. (pl. jabberwokies) invented or meaningless language.
-ORIGIN early 20th cent.: from the title of a nonsense poem in Lewis Caroll's Through the Looking Glass (1871).

mimsyadj. rather feeble and prim or over-restrained.
-ORIGIN 1871: nonsense word coined by Lewis Carroll; a blend of MISERABLE and FLIMSY.

diddlev.informal1 to cheat or swindle. 2N. Amer. waste time. 3 vulgar, slang, chiefly N. Amer. have sex with.
-DERIVATIVES Diddler n.
-ORIGIN C19: prob. from the name of Jeremy Diddler, a character in the farce Raising the Wind (1803) who constantly borrowed small sums of money.

Frankenstein (also Frankenstein's monster) n. a thing that becomes terrifying or destructive to its maker.
-ORIGIN from the title of a novel (1818) by Mary Shelley, whose eponymous main character creates a manlike monster which eventually destroys him.

Generation X n. the generation born between the mid 1960s and the mid 1970s, perceived as being disaffected and directionless.
-DERIVATIVES Generation Xer
-ORIGIN from the novel of the same name (1991) by Douglas Coupland.

hobbitn. a member of an imaginary race similar to humans, of small size and with hairy feet, in stories by J. R. R. Tolkien.
-ORIGIN 1937: invented by Tolkien in his book The Hobbit, and said by him to mean 'hole-dweller'.

humpty-dumptyn. (pl. humpty-dumpties) informal1 short fat person 2 a person or thing that once overthrown cannot be restored.
-ORIGIN C18: from the egg-like nursery-rhyme character Humpty-Dumpty, who fell off a wall and cnould not be put together again.

muggle n. a person without magical powers
(new meaning: 1996; popularized by J. K. Rowling in Harry Potter and the Philospher's Stone. There are, however, two preceding meanings already in the dictionary.)

Land of Oz n. an unreal or magical place.
-ORIGIN a mythical and magical place, first introduced in the children's novel The Wonderful Wizard of Oz (1900) by L. Frank Baum (1856-1919). The legend that Baum came up with the name when he saw a filing cabinet drawer labeled O-Z (below the drawers A-G and H-N) is disputed.

lilliputianadj. trivial or very small. n. a Lilliputian person or thing.
-ORIGIN C18: from the imaginary country of Lilliput in Jonathan Swift's Gulliver's Travels (1726), inhabited by 6-inch high people, +ian

Pollyannan. an excessively cheerful or optimistic person.
-DERIVATIVES Pollyannaish adj. Pollyannaism n.
-ORIGIN the name of the optimistic heroine created by the American author Eleanor H. Porter (1868-1920).

quarkn.Physics any of a group of subatomic particles carrying a fractional electric charge, postulated as building blocks of the hadrons.
-ORIGIN 1960s: invented by the American physicist Murray Gell-Mann and assoc. with the line 'Three quarks for Muster Mark' in Joyce's Finnegans Wake (1939).

robotn. a machine capable of carrying out a complex series of actions automatically, especially one programmable by a computer.
-DERIVATIVES robotization or robotisation n. robotize or robotise v.
-ORIGIN from Czech, from robota 'forced labour'; the term was coined in K. Čapek's play R. U. R. 'Rossum's Universal Robots' (1920).

runcible spoonn. a fork curved like a spoon, with three broad prongs, one of which has a sharpened outer edge for cutting.
-ORIGIN C19: used by Edward Lear, perh. suggested by later C16 rouncival, denoting a learge variety of pea.

Tweedledum and Tweedledeen. a pair of people or things that are virtually indistinguishable.
-ORIGIN orig. names applied to Bononcini and Handel, in a 1725 satire by John Byrom; later used for two identical characters in Lewis Carroll's Through the Looking Glass (1871).

Sometimes literature has the power to form new words, or feature characters who so strongly represent their features that a word is coined in their honour. Some neologisms make it, others don't. Here are some of the words that made in into everyday language prominently enough to have their own dictionary entry.

Rules: It's got to be in the OED listed as originally coming from the work of literature. I may make some allowances to this in some cases though. I'm currently working from a Concise OED 11th edition revised, so it is a few years old and may not have quite every example possible.

Great list, though I would object to Peter Pan and Humpty Dumpty. I've never heard it being used in modern language. Or it maybe it did enter the english language for a period of time, but it certainly isn't in use today, to the best of my knowledge.

Prelude, Casanova would maybe be more appropriate for my Authors in the Dictionary list, but not here. Thanks for the suggestion though. :) Plus, with phrases such as Peter Pan and Humpty Dumpty it completely depends on geographical region, medium and topic. I've heard them and they are in the dictionary, but others may come across them less often or not at all.

Ok, how about 'Behemoth'? It's from that bible book about God and stuff. Off the top of my head, babel, leviathan and sodomy probably originate from it too. I'm not sure if you're counting the bible though!

Updated a new things: added "Land of Oz" and "Shangri-La", also "muggle", though I have noted that there are two meanings that precede the Harry Potter one. Added "chortle" too, thanks for reminding me about that, sleepless, I'm surprised I forgot to add it! :P

How about 'nerd'. It was coined from Dr. Seuss' 1950 children's book "If I Ran The Zoo". ( ”And then, just to show them, I’ll sail to Ka-Troo/And Bring Back an It-Kutch a Preep and a Proo/A Nerkle a Nerd and a Seersucker, too!”)

Shakespeare had a hand in inventing a number of words that are in use today. 'Bump', first used in Romeo and Juliet, 'swagger', first used in A Midsummer Night’s Dream, 'obscene', first used in Love’s Labor’s Lost, and 'luggage', first used in King Henry IV, Part I.

'Yahoo' originated in Gulliver's Travels (1726) by Johnathan Swift. It was used as the name of a neanderthal race of people.